Nick Clegg pleaded for Liberal Democrat activists to “stick with” him today after he suffered a major rebellion over key coalition school reforms.

Delivering his first party conference speech as Deputy Prime Minister, Mr Clegg mounted an impassioned defence of his decision to do a deal with David Cameron’s Tories.

He said voters would never have taken the Lib Dems seriously again if they had passed up the opportunity to govern in the national interest at a time of crisis.

And he insisted the “soul” of the party was alive and well in the coalition despite members’ fears that they were being marginalised and suffering serious political damage.

The address – a text of which was shown to the Prime Minister before being finalised – came after a difficult day for the leadership.

Just hours before Mr Clegg took to the stage in Liverpool, party members overwhelmingly backed a boycott of Tory-inspired plans for a network of “free” schools.

Attempts by the leadership to water down the criticism by removing claims that the policy would increase “social divisiveness and inequity” were resoundingly thrown out following a passionate debate in the packed hall.

Mr Clegg told the audience at the Arena and Convention Centre that he knew many of the coalition’s plans would “provoke controversy” and some Lib Dems were “worried” about the schools plans.

“It wouldn’t be Liberal Democrat conference if we didn’t have a motion that provoked strong passions on both sides,” he said.

“The great thing is that all Liberal Democrats share a passion for education. When it comes to lasting fairness, education is everything.

“So I want to be really clear about what the Government is proposing. It’s not Labour’s academies programme: a few schools singled out for preferential treatment – a cuckoo in the nest that eats up attention and resources.”

He went on: “My vision is that every school, in time, will be equal, every school equally free. But there’s one freedom new schools shouldn’t have: freedom to select.”

Mr Clegg reiterated his reasons for forging the Tory alliance, saying the “chance for change” came, and the Lib Dems “responded with real courage and conviction”. He praised the Conservatives for being willing to “embrace negotiation and compromise”.

“Cynics expected us to back away. Instead, we confounded those who said that coalition Government was impossible. We created a Government which will govern, and govern well, for the next five years,” the Deputy Prime Minister said.

“Hold our nerve and we will have changed British politics for good. Hold our nerve and we will have changed Britain for good.”

The coalition was the “politics our nation needs today”, he said.

“In life, two heads are usually better than one. And in politics, too, when the country faces grave challenges – the deficit, the threat of climate change, a war in Afghanistan, millions of children trapped in disadvantage – two parties acting together can be braver, fairer and bolder than one party acting alone.”